The present disclosure relates to a method for controlling at least one proximity sensor of a wind turbine, the wind turbine including a rotor shaft. Further, the present disclosure relates to a control arrangement. More particularly, the present disclosure relates to a control arrangement for a wind turbine, the wind turbine including a wind rotor shaft. Additionally, the present disclosure relates to a wind turbine. More particularly to a wind turbine including a control device, wherein the control arrangement includes at least one proximity sensor being adapted to measure a radial displacement of the rotor shaft.
Wind rotor blades are connected to a hub which is connected to a wind rotor shaft. Typically, the wind rotor shaft is bended in dependence of the wind in a radial direction of the wind rotor shaft. In some wind turbines an asymmetric load control is provided, for controlling and reducing the loads on the wind turbine. For that reason, wind turbines manufactures have installed proximity sensors, to measure the distance to a flange of the wind rotor shaft, such that from a change of the distance, an asymmetric load of the wind turbine rotor may be reduced. Typically, the proximity sensors may have a special working distance, for example 2 to 10 mm. For example, the proximity sensor location is adjusted while mounting, to be in the limits considering also the turbine operation. Typically, a control of the correct operation of the proximity sensors, for example the relation of distance to output and/or the fixing, is not possible. For example, in case of a laminar flow of wind, the wind turbine rotor is bent constantly in one radial direction of the wind rotor shaft. Thus, the measured distances of the proximity sensors do not change. Thus, the output of the proximity sensors do not change, such that a controller may conclude, that the proximity sensor out of order or do not work properly. A defect sensor for an asymmetric load control may cause a curtailed operation (70% of the rated power) or downtimes.